Abstract
Field measurements showed that the ram penetration of ground was proportional to the ram impact velocity and the impact duration; the impact duration was proportional to the ram mass of unit base area, not influenced by ram drop height. These facts lead to the idea that the ram penetration was proportional to the ram momentum and inversely proportional to the ram base area. This tendency was supported by the centrifuge model test and was also found in the ordinary laboratory compaction test. From these results, estimation of maximum acceleration, maximum impact force and maximum impact stress were discussed.
